A hologram transfer sheet having an optical diffraction structure is conventionally known, which is used when various kinds of pictures, marks and designs are displayed partially or wholly on a surface of a transfer receiving body such as a credit card, a cash card, a portfolio, a packaging and so on by means of a hologram, a diffraction grating or the like. As an example of such a hologram transfer sheet, Japanese Patent Application Laid-Open No. 2002-90276 discloses a hologram transfer sheet in which a peelable layer, a hologram formation layer, a reflective metal thin layer and a thermal adhesion layer are formed in this order on a substrate film.
Also, Japanese Patent Application Laid-Open No. H06(1995)-255268 discloses a thermal transfer sheet (an intermediate transfer recording medium) provided with an image receiving adhesive layer having thermal adhesiveness relative to a transfer receiving body, in which a sublimation transferred image is formed on a transparent metal thin layer of such a hologram transfer sheet.
In the case that an optical diffraction structure such as a hologram or a diffraction grating is transferred onto a transfer receiving body such as a credit card, a cash card or the like by means of such a hologram transfer sheet, the hologram or the diffraction grating with a metallic luster due to the metal thin layer can be formed on the transfer receiving body by aligning the hologram transfer sheet with the transfer receiving body and thermocompressing from the substrate film side of the hologram transfer sheet. However, heat or stress (stress against pressure, tension, shearing force and so on) during the thermocompressing may cause a crack or discoloration of the metal thin layer. Especially, in the case of performing an entire surface transfer by means of a heat roller or the like, the deformation of the substrate is caused by heat, and thereby the crack of the metal thin layer is caused. This results in an appearance of an undesirable mark, which disfigures the external appearance of the hologram transfer portion.
The present invention has been accomplished in view of the above problems. It is therefore an object of the present invention to provide a hologram transfer sheet provided with at least a peelable layer, a relief formation layer having a relief and a metal thin layer, which are formed in this order on a substrate (i.e. a hologram transfer sheet provided with a transfer layer formed on a substrate and having a relief structure such as a hologram and/or a diffraction grating), capable of preventing a crack or discoloration of the metal thin layer which may be caused by heat or stress (stress against pressure, tension, shearing force and so on) when the hologram transfer sheet is aligned with the transfer receiving body to transfer the transfer layer onto the transfer receiving body, and also preventing the disfigurement of the external appearance which may be caused by an undesirable mark due to the crack of the metal thin layer following the deformation of the substrate which may be caused by heat in the case of performing an entire surface transfer by means of a heat roller or the like. It is also an object of the present invention to provide an intermediate transfer recording medium provided with a dye receiving layer on the metal thin layer of such a hologram transfer sheet.